Dental casting-ring



W. H. FARNHAM.

DENTAL CASTING RING.

APPLICATION FILED MAY 15. 1920.

1 ,367,1 30. Patented Feb. 1, 1921.

imme/who e PATENT OFFICE.

WALTER rarmnam, ornucxsronr, MAINE,

DENTAL CASTING-RING.

AppIication filed May 15, 1920. Serial a... 381,552.

To all whom it may concern:

Be itlrnown that I, WA T R H. FARNHAM, a citizen of the United States,residing at Bucksport, in the county of Hancock and State of Maine, haveinvented certain new and useful Improvements in Dental Casting- Rings,of which the following is a specification, reference being had to theaccompany ing drawings.

This invention relates to certain improvements in casting rings and hasrelation more particularly to a device of this general characterespecially designed and adapted for use in forming dental restoration,and it is an object of the invention to provide a novel and improvedring of this general character provided with means whereby vent openingsmay be produced in communication with the mold cavity to facilitate thecasting.

Another object of the invention is to provide a novel and improvedcasting ring provided in its wall at desired points with open ings orslots through each of which is adapted to be directed a wire extendingoutwardly from the wax model and which wire is adapted to be removedafter the mold of porcelain, or the like, has been formed within thering so that a vent opening is provided in communication with the moldcavity whereby the pouring of the molten metal within the mold to effecta casting is materially facilitated and which vent opening alsofacilitates the removal of the melted model or pattern after the moldhas been produced.

The invention consists in the details of construction and in thecombination and arrangement of the several parts of my improved ringwhereby certain important advantages are attained and the devicerendered simpler, less expensive and otherwise more convenient andadvantageous for use, as will be hereinafter more fully set forth.

The novel features of my invention will hereinafter be definitelyclaimed.

In order that my invention may be the better understood, I will nowproceed to describe the same with reference to the accompanyingdrawings, wherein:

Figure 1 is a view in perspective of a dental casting ring constructedin accordance with an embodiment of my invention;

Fig. 2 is a sectional view taken through my improved. ring with the workapplied Specification of Letters Patent.

Patented Fe 11,. 1921.

ime. i

As disclosed in the accompanying drawlngs, R denotes a casting ringconstructed in accordance with an embodiment of my invention and whichis of any preferred length and dlameter and which is preferablycylindrical in form. In the present embodiment of my invention, the ringR is about one inch in length.

One end portion of the ring R has provided in its wall thecircumferentially spaced slots 1 arranged in parallelism and in anallelism with the axis of the ring R. be slots 1 are also preferably ofa length substantlally equal to three-fourths of the length of the ringR although I do not wish to be understood as limiting myself in thisparticular respect.

My improved ring is particularly adapted for use in the casting of agold base or an inlay for a cavity in a tooth. After a wax model orpattern has been produced in a manner well known to the dentalprofession, wires 2 are disposed through the model and extend outwardlythereof a distance suiiicient to pass through the slots 1 and whichadmission of the wires 2 within the slots 1 is permitted in view of thefact that said slots 1 are open at one end. After the model has beenproperly applied within the ring R, the mold is formed in a well knownmanner by porcelain or kindred material and after said mold hassufliciently set, the wires 2 are withdrawn and the model or patternmelted, as is now the practice, and discharged through the conventionalsprue formed in the mold for communication with the mold cavity. Thedischarge of the melted wax is materially facilitated by the ventopenings in communication with the mold chamber produced by the removalof the wires 2. These vent openings also materially facilitate thepouring of the molten metal, such as gold, within the mold chamberduring the casting operation.

From the foregoing description, it is thought to be obvious that a ringconstructed in accordance with my invention, is particularly welladapted for use by reason of the convenience and facility with which itmay be assembled and operated, and it will also be obvious that myinvention is susceptible of some change and modification withouthere-in: and thevent wires shown in posideparting from the principlesand spirit thereof, and for'this reason I do not wish to be understoodas limiting myself to the precise arrangement and formation of theseveral parts herein shown in carrying out my invention in practiceexcept as hereinafter claimed.

'1. As anew article of manufacture a casting ring for forming dentalrestoration having an open slot in its wall through which is adapted toextend an element projecting outwardly from the wax model when appliedwithin the ring, said slot extending longitudinally of the ring and of alength greater than one-half the length of the ring.

2. As a new article of manufacture a casting ring for forming dentalrestoration provided with a plurality of open slots produced in its wallthrough which are adapted to extend elements projecting outwardly fromthe wax model when applied within the ring.

In testimony whereof I hereunto afiix my signature.

WALTER H. FARNHAM.

